The neuroanatomical basis of empathy: is empathy impaired following damage to the ventromedial prefrontal cortex?

Empathy plays a crucial role in our relationships with others and enhances personal well-being. The brain areas that are critical for the experience of on-line empathy and empathic behavior are not known. The current study investigated the neural substrates of empathy through the examination of whether the ventromedial prefrontal cortex (VMPC) is critical for empathy. For the first time, on-line empathic experience and behavior were measured in patients with brain damage to the VMPC.

Six patients with bilateral damage to the VMPC were case-matched on specific demographic and neuropsychological criteria to two comparison groups: a brain damage group and a healthy adult group. On-line empathy was induced in an ecologically-valid manner in which the participant experienced live the sorrow of another person. The participant thought they would be playing an economic game against two opponents. However, during the study the participant overheard their game opponent experience deep sadness, revealing that it was the anniversary of their son's death (empathic induction.) A comparison neutral induction involved the participant overhearing their opponent converse with the research assistant about a neutral topic. On-line empathic experience was measured by a questionnaire completed before and after the inductions. Empathic behavior was measured implicitly through an economic game. It was defined as the degree of behavioral change on the game as a result of the empathic induction (after accounting for baseline behavior.) The economic game used to measure empathic behavior was the Repeated Fixed Opponent variant of the well-validated Ultimatum Game. This particular variant had not been studied in participants of a similar age range to the patient sample (younger and older adults). Furthermore, there is evidence for some aging-related differences in behavior on economic games, providing additional rationale to examine the behavior of healthy younger and older adults on the game. Consequently, game behavior of younger and older adults was measured and then used to implement a model of healthy game behavior in the experiment that investigated empathy in patients with damage to the VMPC.

Patients with damage to the VMPC experienced poor on-line empathy and showed poor empathic behavior. Patients with brain damage to the VMPC reported significantly less on-line empathy than patients with brain damage to other regions. Empathic behavior was not shown by patients with damage to the VMPC as a result of the empathic induction and their behavior was significantly different from both the healthy and the brain damage comparison groups which showed increased empathic behavior due to the empathic induction. A specific role for the VMPC region in empathy was demonstrated by the finding that patients with damage to this region had less on-line empathy and empathic behavior than patients with brain damage to other regions. This study showed that the VMPC region of the brain is critical for empathy. Further research is needed to elucidate whether patients with brain damage to the VMPC show decreased empathic behavior in all domains or whether it is specific to monetary decision-making.